1. Technical Field
The present invention relates to an image projection apparatus and an image projection system.
2. Related Art
A coaxial illumination image-taking apparatus miniaturized by partly sharing an optical path between an illumination system and an image-taking system is known.
This conventional coaxial illumination image-taking apparatus has a housing provided with an opening, a camera disposed in the housing so that an optical axis thereof passes through the opening, a half mirror disposed in the housing to be placed on the optical axis of the camera, a light emitting diode disposed in the housing so that output light thereof is reflected by the half mirror, and that the reflected light is output externally from the opening, a light attenuation filter which is disposed to be inclined to the optical axis of the light emitting diode and is adapted to attenuate light rays transmitted by the half mirror among light rays output from the light emitting diode, and a nonreflecting element disposed on the optical axis of light reflected by the light attenuation filter.
According to the coaxial illumination image-taking apparatus, a part of light emitted from the light emitting diode is reflected by the half mirror and is externally output from the opening. However, light transmitted by the half mirror reaches the light attenuation filter and is then attenuated. Light having been insufficiently attenuated is absorbed by the nonreflecting element. Thus, a part of the light emitted from the light emitting diode can be suppressed from becoming stray light. Also, the stray light can be prevented from being incident upon the camera.